rsync - Oct 2007 - symlinks that become directories question

If I have a backup script that does the following:
(latest 2.6.9 rsync)

rsync --archive --hard-links --force --ignore-errors --numeric-ids 
--keep-dirlinks --delete / /backup

I've found that if there is a symlink in place that gets backed up (which 
goes fine), i.e.:
homelink -> /home/

and then that symlink gets changed into an actual directory, i.e.:
rm homelink
mkdir homelink

rsync will actually delete everything in the directory that the symlink 
pointed to (in the above case it deletes /home).

Is the workaround to use --delete-after to avoid this behavior, or is my 
logic flawed in using rsync with the command above to produce a mirror 
copy of an entire server to a backup drive? Thanks.

Rob

On Mon, 2007-10-29 at 13:15 -0400, rob@mangiafico.net wrote:
> If I have a backup script that does the following:
> (latest 2.6.9 rsync)
> 
> rsync --archive --hard-links --force --ignore-errors --numeric-ids 
> --keep-dirlinks --delete / /backup
> 
> I've found that if there is a symlink in place that gets backed up
(which
> goes fine), i.e.:
> homelink -> /home/
> 
> and then that symlink gets changed into an actual directory, i.e.:
> rm homelink
> mkdir homelink
I assume this directory is empty? 
> rsync will actually delete everything in the directory that the symlink 
> pointed to (in the above case it deletes /home).
Rsync's behavior, however surprising, is correct.  Since you passed
--keep-dirlinks, rsync is mapping the source's "homelink"
directory to
the target directory of the destination's "homelink" symlink,
i.e., /home.  (Without --keep-dirlinks, rsync would first replace the
destination's "homelink" with an actual directory.)  Since you
passed
--delete, rsync deletes any and all files from /home that lack
counterparts in the source's "homelink".
> Is the workaround to use --delete-after to avoid this behavior, or is my 
> logic flawed in using rsync with the command above to produce a mirror 
> copy of an entire server to a backup drive?
--delete-after gives the same behavior.  To stop rsync from following
the destination's symlink to /home, you will have to remove
--keep-dirlinks.  Unfortunately, if there are other dirlinks that you
*do* need to keep, you will have to do something more complicated.

Matt

On Tue, 30 Oct 2007, Matt McCutchen wrote:
> On Mon, 2007-10-29 at 13:15 -0400, rob@mangiafico.net wrote:
> > If I have a backup script that does the following:
> > (latest 2.6.9 rsync)
> >
> > rsync --archive --hard-links --force --ignore-errors --numeric-ids
> > --keep-dirlinks --delete / /backup
> > 
> > I've found that if there is a symlink in place that gets backed up
(which
> > goes fine), i.e.:
> > homelink -> /home/
> >
> > and then that symlink gets changed into an actual directory, i.e.: 
> > rm homelink
> > mkdir homelink
>
> I assume this directory is empty?
Yes.
> > rsync will actually delete everything in the directory that the 
symlink
> > pointed to (in the above case it deletes /home).
>
> Rsync's behavior, however surprising, is correct.  Since you passed
> --keep-dirlinks, rsync is mapping the source's "homelink"
directory to
> the target directory of the destination's "homelink" symlink,
> i.e., /home.  (Without --keep-dirlinks, rsync would first replace the
> destination's "homelink" with an actual directory.)  Since
you passed
> --delete, rsync deletes any and all files from /home that lack
> counterparts in the source's "homelink".
> 
> > Is the workaround to use --delete-after to avoid this behavior, or is 
my
> > logic flawed in using rsync with the command above to produce a mirror
> > copy of an entire server to a backup drive?
> 
> --delete-after gives the same behavior.  To stop rsync from following
> the destination's symlink to /home, you will have to remove
> --keep-dirlinks.  Unfortunately, if there are other dirlinks that you
> *do* need to keep, you will have to do something more complicated.
Thanks for the explanation. Since all we're doing is using rsync to make a
backup on a second drive, and this backup will be used for either
file/directory restores, or in the event of a primary drive failure, used
in a bare metal restore situation, I believe leaving off
"--keep-dirlinks"
will not cause any problems, as the symlinks that point to directories on
the primary drive will still be intact on the backup drive, and can be
restored "as is" on a restore, correct? We don't need rsync to
follow the
symlink, as we're already backing up all the data on the OS.

Rob